Mechanism for facilitating spin mode-based dynamic updating of application servers in an on-demand services environment

ABSTRACT

In accordance with embodiments, there are provided mechanisms and methods for facilitating spin mode-based dynamic updating of application servers. In one embodiment and by way of example, a method includes upgrading a first set of application servers of a plurality of application servers at one or more computing devices, holding a first set of requests received at the first set of application servers from being processed while the first set of application servers is being upgraded, and upgrading a second set of application servers of the plurality of application servers upon completion of the first set of application servers. The method may further include holding a second set of requests received at the second set of application servers from being processed while the second set of application servers is being upgraded, and resuming processing of the first set of requests at the upgraded first set of application servers.

CLAIM OF PRIORITY

This application claims the benefit of U.S. Provisional PatentApplication No. 61/528,513, entitled “Methods and Systems for ZeroDowntime Using a Spin Mode in an On-Demand Service Environment” byKarthik Rajan, filed Aug. 29, 2011 (Attorney Docket No. 8956P069Z), theentire contents of which are incorporated herein by reference andpriority is claimed thereof.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

TECHNICAL FIELD

One or more implementations relate generally to data management and,more specifically, to a mechanism for facilitating spin mode-baseddynamic updating of application servers in an on-demand servicesenvironment.

BACKGROUND

It is well-known that updating of application servers can cause plentyof downtime that is expensive and inefficient. Although several attemptshave been made to simplify this often complex process of updating anapplication server, these attempts have not been successful insignificantly reducing the downtime associated with the process.

The subject matter discussed in the background section should not beassumed to be prior art merely as a result of its mention in thebackground section. Similarly, a problem mentioned in the backgroundsection or associated with the subject matter of the background sectionshould not be assumed to have been previously recognized in the priorart. The subject matter in the background section merely representsdifferent approaches, which in and of themselves may also be inventions.

In conventional database systems, users access their data resources inone logical database. A user of such a conventional system typicallyretrieves data from and stores data on the system using the user's ownsystems. A user system might remotely access one of a plurality ofserver systems that might in turn access the database system. Dataretrieval from the system might include the issuance of a query from theuser system to the database system. The database system might processthe request for information received in the query and send to the usersystem information relevant to the request. The secure and efficientretrieval of accurate information and subsequent delivery of thisinformation to the user system has been and continues to be a goal ofadministrators of database systems. Unfortunately, conventional databaseapproaches are associated with various limitations.

SUMMARY

In accordance with embodiments, there are provided mechanisms andmethods for facilitating spin mode-based dynamic updating of applicationservers in an on-demand services environment. In one embodiment and byway of example, a method includes upgrading a first set of applicationservers of a plurality of application servers at one or more computingdevices, holding a first set of requests received at the first set ofapplication servers from being processed while the first set ofapplication servers is being upgraded, and upgrading a second set ofapplication servers of the plurality of application servers uponcompletion of the first set of application servers. The method mayfurther include holding a second set of requests received at the secondset of application servers from being processed while the second set ofapplication servers is being upgraded, and resuming processing of thefirst set of requests at the upgraded first set of application servers.

While the present invention is described with reference to an embodimentin which techniques for facilitating management of data in an on-demandservices environment are implemented in a system having an applicationserver providing a front end for an on-demand database service capableof supporting multiple tenants, the present invention is not limited tomulti-tenant databases nor deployment on application servers.Embodiments may be practiced using other database architectures, i.e.,ORACLE®, DB2® by IBM and the like without departing from the scope ofthe embodiments claimed.

Any of the above embodiments may be used alone or together with oneanother in any combination. Inventions encompassed within thisspecification may also include embodiments that are only partiallymentioned or alluded to or are not mentioned or alluded to at all inthis brief summary or in the abstract. Although various embodiments ofthe invention may have been motivated by various deficiencies with theprior art, which may be discussed or alluded to in one or more places inthe specification, the embodiments of the invention do not necessarilyaddress any of these deficiencies. In other words, different embodimentsof the invention may address different deficiencies that may bediscussed in the specification. Some embodiments may only partiallyaddress some deficiencies or just one deficiency that may be discussedin the specification, and some embodiments may not address any of thesedeficiencies.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following drawings like reference numbers are used to refer tolike elements. Although the following figures depict various examples,one or more implementations are not limited to the examples depicted inthe figures.

FIG. 1 illustrates a computing system employing a spin mode updatemechanism according to one embodiment;

FIG. 2 illustrates a spin mode update mechanism employed at a computingdevice according to one embodiment;

FIG. 3 illustrate a transaction sequence for performing spin mode-baseddynamic updating of application servers using a spin mode updatemechanism according to one embodiment;

FIG. 4 illustrates a method for spin mode-based dynamic updating ofapplication servers using a spin mode update mechanism according to oneembodiment;

FIG. 5 illustrates a computer system according to one embodiment;

FIG. 6 illustrates a block diagram of an environment wherein anon-demand database service might be used according to one embodiment;and

FIG. 7 illustrates a block diagram of an embodiment of elements ofenvironment of FIG. 6 and various possible interconnections betweenthese elements according to one embodiment.

DETAILED DESCRIPTION

Methods and systems are provided for facilitating spin mode-baseddynamic updating of application servers in an on-demand servicesenvironment. In one embodiment and by way of example, a method includesupgrading a first set of application servers of a plurality ofapplication servers at one or more computing devices, holding a firstset of requests received at the first set of application servers frombeing processed while the first set of application servers is beingupgraded, and upgrading a second set of application servers of theplurality of application servers upon completion of the first set ofapplication servers. The method may further include holding a second setof requests received at the second set of application servers from beingprocessed while the second set of application servers is being upgraded,and resuming processing of the first set of requests at the upgradedfirst set of application servers.

As used herein, a term multi-tenant database system refers to thosesystems in which various elements of hardware and software of thedatabase system may be shared by one or more customers. For example, agiven application server may simultaneously process requests for a greatnumber of customers, and a given database table may store rows for apotentially much greater number of customers. As used herein, the termquery plan refers to a set of steps used to access information in adatabase system.

Next, mechanisms and methods for spin mode-based dynamic updating ofapplication servers in an on-demand service environment having amulti-tenant database system will be described with reference to exampleembodiments.

FIG. 1 illustrates a computing system employing a spin mode updatemechanism according to one embodiment. In one embodiment, a computingdevice 100 serves as a host machine hosting a spin mode update mechanism(“spin mode mechanism”) 110 to facilitate dynamic, customized, andefficient updating of application servers without having to require anydowntime. Computing device 100 serving as a host machine may includeserver computers, desktop computers, cluster-based computers, laptopcomputing devices (e.g., notebooks, netbooks, etc.), set-top boxes(e.g., Internet-based cable television set-top boxes, etc.), and thelike. Computing device 100 may also include mobile computing devices,such as cellular phones including smartphones (e.g., iPhone®,BlackBerry®, etc.), handheld computing devices, personal digitalassistants (PDAs), etc., tablet computers (e.g., iPad®, Samsung® GalaxyTab®, etc.), laptop computers, e-readers (e.g., Kindle®, Nook®, etc.),Global Positioning System (GPS)-based navigation systems, etc.

Computing device 100 includes an operating system 106 serving as aninterface between any hardware or physical resources of the computerdevice 100 and a user. Computing device 100 further includes one or moreprocessors 102, memory devices 104, network devices, drivers, or thelike, as well as input/output (I/O) sources 108, such as touchscreens,touch panels, touch pads, virtual or regular keyboards, virtual orregular mice, etc. It is to be noted that terms like “node”, “computingnode”, “client”, “client device”, “server”, “server device”, “machine”,“host machine”, “device”, “computing device”, “computer”, “computingsystem”, “multi-tenant on-demand data system”, and the like, are usedinterchangeably and synonymously throughout this document. It is to befurther noted that terms like “application”, “software application”,“program”, “software program”, “package”, and “software package” areused interchangeably and synonymously throughout this document.

FIG. 2 illustrates a spin mode update mechanism employed at a computingdevice according to one embodiment. In one embodiment, a spin modeupdate mechanism 110 includes various components 202, 204, 206, 208, 210and 212 to offer a number of services to facilitate zero downtime updateof application servers in a multi-tenant database system in an on-demandservices environment. The spin mode mechanism 110 includes a selectionand retirement module 202 to select any number of application serversfor updating. For example, a cluster of 10 application servers may needan updating to a new version. Using this example, a selection andretirement module 202 of the spin mode mechanism 110 may choose one ormore application servers from the cluster as a first set of applicationservers (e.g., 5 application servers labeled as application servers 1-5)that are to be upgraded to the new version. Once selected, the selectionand retirement module 202 retires the first set of application serversto be updated.

The retired application servers of the first set are then upgraded tothe new version by an upgrade module 204. While the first set ofapplication servers is being upgraded to the new version, a processingmodule 206 facilitates the remaining application servers (e.g., theremaining 5 application servers labeled as servers 6-10) of the clusterto continue to process any processing requests received at the remainingapplication servers 6-10. This way, the processing of these requests isconsistent with the published version of application servers that is thecurrent version of application servers 6-10 (because they have yet to beupgraded to the new version). The published version may be published bya system or database associated with the entire cluster of applicationservers, such as application servers 1-10.

While these processing requests get processed by the second set ofapplication servers, any processing requests being received at the firstset of application servers are put on hold in a first spin mode by aspin mode module 208. In addition to having a virtually zero downtimewhen upgrading application servers, this novel spin mode technique alsoprevents the processing requests from getting processed by multipleversions of application servers. A processing request refers to anyrequest that is received from a user and that requires an applicationserver to provide services, such as a user placing a request, via acomputing device, to surf a website, etc.

Once the upgrading or updating of the first set of application serversis completed, the second set of application servers is retired, by theselection and retirement module 202, for potential upgrading orupdating. It is to be noted that words like “upgrade” and “update” maybe used interchangeably and synonymously throughout the document. Oncethe second set of application servers is retired, any processing requestbeing received at any of the application servers 6-10 of the second setare put on hold in a second spin mode by the spin mode module 208. Thisis again so that the downtime can be reduced to zero while at the sametime preventing the processing requests from being processed by multipleversions of application servers. A publication update module 210 updatesthe published version to be the same (e.g., version 2) as that of therecently upgraded application servers 1-5 of the first set ofapplication servers. In one embodiment, the spin mode module 208 endsthe first spin mode holding the processing requests bound for the firstset of application servers from being processed so that those and anynew processing request for the first set can now be processed by the newversion of the newly-upgraded first set of application servers 1-5.

Similarly, once the second set of application servers is upgraded to thenew version, the second spin mode is terminated by the spin mode module208 so that any processing requests on hold and any new processingrequests being received at the second set of application servers can nowbe processed by the new-versioned newly-upgraded second set ofapplication servers 6-10. In one embodiment, using the aforementionedtechniques of the spin mode upgrade mechanism 110, the entire cluster ofapplication servers is upgraded with zero downtime and in a way that anyprocessing requests received at these application servers are processedby the single published version of the application servers.

The spin mode update mechanism 110 further includes a compatibilitymodule 212 to allow the spin mode update mechanism 110 to be dynamicallyand automatically compatible with any type of Internet or hotspotservice providers (e.g., telecommunication companies, Internet serviceproviders, etc.), computer devices (e.g., computer device 100 of FIG.1), application servers (such as by Java®, Oracle (e.g., WebLogic®,etc.), International Business Machines (IBM®) (e.g., WebSpere®, etc.),Microsoft® (e.g., .NET® Framework, etc.), SAP® (e.g., ApplicationBusiness Application Programming (ABAP®), etc.), Hypertext Preprocessor(PHP®), etc., and the like.

It is contemplated that any number and type of components may be addedto and removed from the spin mode update mechanism 110 to facilitatezero downtime dynamic upgrade of application servers. For brevity,clarity, ease of understanding and to stay focused on the spin modeupdate mechanism 110, many of the standard or known components, such asthose of a computing device, are not shown or discussed here. It iscontemplated that embodiments of the invention are not limited to anyparticular technology or standard and is dynamic enough to adopt andadapt to the changing technology and standards.

FIG. 3 illustrates a transaction sequence for performing spin mode-baseddynamic updating of application servers using a spin mode updatemechanism according to one embodiment. In the illustrated transactionsequence 300, the spin mode update mechanism 110 retires 306 set A 302of a cluster of application servers for a potential upgrade to a newversion. Having retired set A 302, any processing requests receivedbeing received at set A 302 are put in spin mode A 308 to be put onhold, while processing requests being received at set B 304 continue tobe processed 310 using the current (published) version. Set Aapplication servers 302 are upgraded 312, while set B applicationservers 304 are retired 314 for a potential upgrade. Upon retirement ofset B 304, any processing requests now being received at set B 304 areput in spin mode B 316 to be put on hold.

Meanwhile, in one embodiment, the published version (e.g., as publishedby the database associated with or the system that runs the cluster ofapplication servers 302, 304) is changed to the new version 318 tocorrespond to the newly-upgraded version of the application serversbelonging to set A 306. With the updating of the publish version 318,spin mode A is ended 320 so that the application servers of set A 302can now resume processing 322 of any processing requests at set A 302.These processing requests are processed 322 using the new upgradedversion of the application servers of set A 302, while the applicationservers of set B 304 are upgraded 324 to the new version. Once theupgrade of the application servers of set B 304 is completed 326, spinmode B is also terminated 328 so that the processing request on hold andany new processing requests can be processed 330 at the applicationsevers of B 304 using the new published version. The transactionsequence 300 ends as all clustered application servers 302, 304 areupgraded to the new version and can now process their respectiveprocessing requests based on the new version, which is also thepublished version.

FIG. 4 illustrates a method for spin mode-based dynamic updating ofapplication servers using a spin mode update mechanism according to oneembodiment. Method 400 may be performed by processing logic that maycomprise hardware (e.g., circuitry, dedicated logic, programmable logic,microcode, etc.), software (such as instructions run on a processingdevice), or a combination thereof, such as firmware or functionalcircuitry within hardware devices. In one embodiment, method 400 isperformed by the spin mode update mechanism 110 of FIG. 1.

Method 400 beings at block 405 with selecting and retiring a first setof application servers of a cluster of application servers. At block410, the first set of applications servers is upgraded from a current(published) version to a new version. At block 415, a first set ofrequests being received at the first set of application servers is held(from being processed) in a first spin mode while the first set ofapplication servers is being upgraded. At block 420, a second set ofrequests being received at a second set of application servers (havingthe current published version) are continuously processed as the firstset of application servers is being upgraded. At block 425, thepublished version is updated or changed from the current version to thenew version once the first set of application servers has been upgradedto the new version.

At block 430 the second set of application servers (representing therest of the cluster of application servers) is selected and retired oncethe published version has been changed to the new version. At block 435,first spin mode is ended and the processing of the first set of requestsbeing received at the first set of application servers (now upgraded tothe new published version) is resumed. At block 440, the second set ofapplication servers is upgraded from the old version (that is no longercurrent or published) to the new version (that is now published). Atblock 445, the second set of requests being received at the second setof application servers is held (from being processed) in a second spinmode as the second set of application servers is being upgraded. Atblock 450, the second spin mode is terminated and the processing of thesecond set of requests being received at the second set of applicationservers is resumed once the second set of application servers isupgraded (to the new published version which is the same as that of theupgraded first set of application servers).

FIG. 5 illustrates a diagrammatic representation of a machine 500 in theexemplary form of a computer system, in accordance with one embodiment,within which a set of instructions, for causing the machine 500 toperform any one or more of the methodologies discussed herein, may beexecuted. Machine 500 is the same as or similar to computing device 100of FIG. 1. In alternative embodiments, the machine may be connected(e.g., networked) to other machines in a Local Area Network (LAN), anintranet, an extranet, or the Internet. The machine may operate in thecapacity of a server or a client machine in a client-server networkenvironment, or as a peer machine in a peer-to-peer (or distributed)network environment or as a server or series of servers within anon-demand service environment, including an on-demand environmentproviding multi-tenant database storage services. Certain embodiments ofthe machine may be in the form of a personal computer (PC), a tablet PC,a set-top box (STB), a Personal Digital Assistant (PDA), a cellulartelephone, a web appliance, a server, a network router, switch orbridge, computing system, or any machine capable of executing a set ofinstructions (sequential or otherwise) that specify actions to be takenby that machine. Further, while only a single machine is illustrated,the term “machine” shall also be taken to include any collection ofmachines (e.g., computers) that individually or jointly execute a set(or multiple sets) of instructions to perform any one or more of themethodologies discussed herein.

The exemplary computer system 500 includes a processor 502, a mainmemory 504 (e.g., read-only memory (ROM), flash memory, dynamic randomaccess memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM(RDRAM), etc., static memory such as flash memory, static random accessmemory (SRAM), volatile but high-data rate RAM, etc.), and a secondarymemory 518 (e.g., a persistent storage device including hard disk drivesand persistent multi-tenant data base implementations), whichcommunicate with each other via a bus 530. Main memory 504 includesemitted execution data 524 (e.g., data emitted by a logging framework)and one or more trace preferences 523 which operate in conjunction withprocessing logic 526 and processor 502 to perform the methodologiesdiscussed herein.

Processor 502 represents one or more general-purpose processing devicessuch as a microprocessor, central processing unit, or the like. Moreparticularly, the processor 502 may be a complex instruction setcomputing (CISC) microprocessor, reduced instruction set computing(RISC) microprocessor, very long instruction word (VLIW) microprocessor,processor implementing other instruction sets, or processorsimplementing a combination of instruction sets. Processor 502 may alsobe one or more special-purpose processing devices such as an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA), a digital signal processor (DSP), network processor, or thelike. Processor 502 is configured to execute the processing logic 526for performing the operations and functionality of dynamic visualworkflow mechanism 110 as described with reference to FIGS. 1 and 2 andother figures discussed herein.

The computer system 500 may further include a network interface card508. The computer system 500 also may include a user interface 510 (suchas a video display unit, a liquid crystal display (LCD), or a cathoderay tube (CRT)), an alphanumeric input device 512 (e.g., a keyboard), acursor control device 514 (e.g., a mouse), and a signal generationdevice 516 (e.g., an integrated speaker). The computer system 500 mayfurther include peripheral device 536 (e.g., wireless or wiredcommunication devices, memory devices, storage devices, audio processingdevices, video processing devices, etc. The computer system 500 mayfurther include a Hardware based API logging framework 534 capable ofexecuting incoming requests for services and emitting execution dataresponsive to the fulfillment of such incoming requests.

The secondary memory 518 may include a machine-readable storage medium(or more specifically a machine-accessible storage medium) 531 on whichis stored one or more sets of instructions (e.g., software 522)embodying any one or more of the methodologies or functions of dynamicvisual workflow mechanism 110 as described with reference to FIGS. 1 and2 and other figures described herein. The software 522 may also reside,completely or at least partially, within the main memory 504 and/orwithin the processor 502 during execution thereof by the computer system500, the main memory 504 and the processor 502 also constitutingmachine-readable storage media. The software 522 may further betransmitted or received over a network 520 via the network interfacecard 508. The machine-readable storage medium 531 may include transitoryor non-transitory machine-readable storage media.

Portions of various embodiments of the present invention may be providedas a computer program product, which may include a computer-readablemedium having stored thereon computer program instructions, which may beused to program a computer (or other electronic devices) to perform aprocess according to the embodiments of the present invention. Themachine-readable medium may include, but is not limited to, floppydiskettes, optical disks, compact disk read-only memory (CD-ROM), andmagneto-optical disks, ROM, RAM, erasable programmable read-only memory(EPROM), electrically EPROM (EEPROM), magnet or optical cards, flashmemory, or other type of media/machine-readable medium suitable forstoring electronic instructions.

The techniques shown in the figures can be implemented using code anddata stored and executed on one or more electronic devices (e.g., an endstation, a network element). Such electronic devices store andcommunicate (internally and/or with other electronic devices over anetwork) code and data using computer-readable media, such asnon-transitory computer-readable storage media (e.g., magnetic disks;optical disks; random access memory; read only memory; flash memorydevices; phase-change memory) and transitory computer-readabletransmission media (e.g., electrical, optical, acoustical or other formof propagated signals—such as carrier waves, infrared signals, digitalsignals). In addition, such electronic devices typically include a setof one or more processors coupled to one or more other components, suchas one or more storage devices (non-transitory machine-readable storagemedia), user input/output devices (e.g., a keyboard, a touchscreen,and/or a display), and network connections. The coupling of the set ofprocessors and other components is typically through one or more bussesand bridges (also termed as bus controllers). Thus, the storage deviceof a given electronic device typically stores code and/or data forexecution on the set of one or more processors of that electronicdevice. Of course, one or more parts of an embodiment of the inventionmay be implemented using different combinations of software, firmware,and/or hardware.

FIG. 6 illustrates a block diagram of an environment 610 wherein anon-demand database service might be used. Environment 610 may includeuser systems 612, network 614, system 616, processor system 617,application platform 618, network interface 620, tenant data storage622, system data storage 624, program code 626, and process space 628.In other embodiments, environment 610 may not have all of the componentslisted and/or may have other elements instead of, or in addition to,those listed above.

Environment 610 is an environment in which an on-demand database serviceexists. User system 612 may be any machine or system that is used by auser to access a database user system. For example, any of user systems612 can be a handheld computing device, a mobile phone, a laptopcomputer, a work station, and/or a network of computing devices. Asillustrated in herein FIG. 6 (and in more detail in FIG. 7) user systems612 might interact via a network 614 with an on-demand database service,which is system 616.

An on-demand database service, such as system 616, is a database systemthat is made available to outside users that do not need to necessarilybe concerned with building and/or maintaining the database system, butinstead may be available for their use when the users need the databasesystem (e.g., on the demand of the users). Some on-demand databaseservices may store information from one or more tenants stored intotables of a common database image to form a multi-tenant database system(MTS). Accordingly, “on-demand database service 616” and “system 616”will be used interchangeably herein. A database image may include one ormore database objects. A relational database management system (RDMS) orthe equivalent may execute storage and retrieval of information againstthe database object(s). Application platform 618 may be a framework thatallows the applications of system 616 to run, such as the hardwareand/or software, e.g., the operating system. In an embodiment, on-demanddatabase service 616 may include an application platform 618 thatenables creation, managing and executing one or more applicationsdeveloped by the provider of the on-demand database service, usersaccessing the on-demand database service via user systems 612, or thirdparty application developers accessing the on-demand database servicevia user systems 612.

The users of user systems 612 may differ in their respective capacities,and the capacity of a particular user system 612 might be entirelydetermined by permissions (permission levels) for the current user. Forexample, where a salesperson is using a particular user system 612 tointeract with system 616, that user system has the capacities allottedto that salesperson. However, while an administrator is using that usersystem to interact with system 616, that user system has the capacitiesallotted to that administrator. In systems with a hierarchical rolemodel, users at one permission level may have access to applications,data, and database information accessible by a lower permission leveluser, but may not have access to certain applications, databaseinformation, and data accessible by a user at a higher permission level.Thus, different users will have different capabilities with regard toaccessing and modifying application and database information, dependingon a user's security or permission level.

Network 614 is any network or combination of networks of devices thatcommunicate with one another. For example, network 614 can be any one orany combination of a LAN (local area network), WAN (wide area network),telephone network, wireless network, point-to-point network, starnetwork, token ring network, hub network, or other appropriateconfiguration. As the most common type of computer network in currentuse is a TCP/IP (Transfer Control Protocol and Internet Protocol)network, such as the global internetwork of networks often referred toas the “Internet” with a capital “I,” that network will be used in manyof the examples herein. However, it should be understood that thenetworks that one or more implementations might use are not so limited,although TCP/IP is a frequently implemented protocol.

User systems 612 might communicate with system 616 using TCP/IP and, ata higher network level, use other common Internet protocols tocommunicate, such as HTTP, FTP, AFS, WAP, etc. In an example where HTTPis used, user system 612 might include an HTTP client commonly referredto as a “browser” for sending and receiving HTTP messages to and from anHTTP server at system 616. Such an HTTP server might be implemented asthe sole network interface between system 616 and network 614, but othertechniques might be used as well or instead. In some implementations,the interface between system 616 and network 614 includes load sharingfunctionality, such as round-robin HTTP request distributors to balanceloads and distribute incoming HTTP requests evenly over a plurality ofservers. At least as for the users that are accessing that server, eachof the plurality of servers has access to the MTS′ data; however, otheralternative configurations may be used instead.

In one embodiment, system 616, shown in FIG. 6, implements a web-basedcustomer relationship management (CRM) system. For example, in oneembodiment, system 616 includes application servers configured toimplement and execute CRM software applications as well as providerelated data, code, forms, webpages and other information to and fromuser systems 612 and to store to, and retrieve from, a database systemrelated data, objects, and Webpage content. With a multi-tenant system,data for multiple tenants may be stored in the same physical databaseobject, however, tenant data typically is arranged so that data of onetenant is kept logically separate from that of other tenants so that onetenant does not have access to another tenant's data, unless such datais expressly shared. In certain embodiments, system 616 implementsapplications other than, or in addition to, a CRM application. Forexample, system 616 may provide tenant access to multiple hosted(standard and custom) applications, including a CRM application. User(or third party developer) applications, which may or may not includeCRM, may be supported by the application platform 618, which managescreation, storage of the applications into one or more database objectsand executing of the applications in a virtual machine in the processspace of the system 616.

One arrangement for elements of system 616 is shown in FIG. 6, includinga network interface 620, application platform 618, tenant data storage622 for tenant data 623, system data storage 624 for system data 625accessible to system 616 and possibly multiple tenants, program code 626for implementing various functions of system 616, and a process space628 for executing MTS system processes and tenant-specific processes,such as running applications as part of an application hosting service.Additional processes that may execute on system 616 include databaseindexing processes.

Several elements in the system shown in FIG. 6 include conventional,well-known elements that are explained only briefly here. For example,each user system 612 could include a desktop personal computer,workstation, laptop, PDA, cell phone, or any wireless access protocol(WAP) enabled device or any other computing device capable ofinterfacing directly or indirectly to the Internet or other networkconnection. User system 612 typically runs an HTTP client, e.g., abrowsing program, such as Microsoft's Internet Explorer browser,Netscape's Navigator browser, Opera's browser, or a WAP-enabled browserin the case of a cell phone, PDA or other wireless device, or the like,allowing a user (e.g., subscriber of the multi-tenant database system)of user system 612 to access, process and view information, pages andapplications available to it from system 616 over network 614. Each usersystem 612 also typically includes one or more user interface devices,such as a keyboard, a mouse, trackball, touch pad, touch screen, pen orthe like, for interacting with a graphical user interface (GUI) providedby the browser on a display (e.g., a monitor screen, LCD display, etc.)in conjunction with pages, forms, applications and other informationprovided by system 616 or other systems or servers. For example, theuser interface device can be used to access data and applications hostedby system 616, and to perform searches on stored data, and otherwiseallow a user to interact with various GUI pages that may be presented toa user. As discussed above, embodiments are suitable for use with theInternet, which refers to a specific global internetwork of networks.However, it should be understood that other networks can be used insteadof the Internet, such as an intranet, an extranet, a virtual privatenetwork (VPN), a non-TCP/IP based network, any LAN or WAN or the like.

According to one embodiment, each user system 612 and all of itscomponents are operator configurable using applications, such as abrowser, including computer code run using a central processing unitsuch as an Intel Pentium® processor or the like. Similarly, system 616(and additional instances of an MTS, where more than one is present) andall of their components might be operator configurable usingapplication(s) including computer code to run using a central processingunit such as processor system 617, which may include an Intel Pentium®processor or the like, and/or multiple processor units. A computerprogram product embodiment includes a machine-readable storage medium(media) having instructions stored thereon/in which can be used toprogram a computer to perform any of the processes of the embodimentsdescribed herein. Computer code for operating and configuring system 616to intercommunicate and to process webpages, applications and other dataand media content as described herein are preferably downloaded andstored on a hard disk, but the entire program code, or portions thereof,may also be stored in any other volatile or non-volatile memory mediumor device as is well known, such as a ROM or RAM, or provided on anymedia capable of storing program code, such as any type of rotatingmedia including floppy disks, optical discs, digital versatile disk(DVD), compact disk (CD), microdrive, and magneto-optical disks, andmagnetic or optical cards, nanosystems (including molecular memory ICs),or any type of media or device suitable for storing instructions and/ordata. Additionally, the entire program code, or portions thereof, may betransmitted and downloaded from a software source over a transmissionmedium, e.g., over the Internet, or from another server, as is wellknown, or transmitted over any other conventional network connection asis well known (e.g., extranet, VPN, LAN, etc.) using any communicationmedium and protocols (e.g., TCP/IP, HTTP, HTTPS, Ethernet, etc.) as arewell known. It will also be appreciated that computer code forimplementing embodiments can be implemented in any programming languagethat can be executed on a client system and/or server or server systemsuch as, for example, C, C++, HTML, any other markup language, Java™,JavaScript, ActiveX, any other scripting language, such as VBScript, andmany other programming languages as are well known may be used. (Java™is a trademark of Sun Microsystems, Inc.).

According to one embodiment, each system 616 is configured to providewebpages, forms, applications, data and media content to user (client)systems 612 to support the access by user systems 612 as tenants ofsystem 616. As such, system 616 provides security mechanisms to keepeach tenant's data separate unless the data is shared. If more than oneMTS is used, they may be located in close proximity to one another(e.g., in a server farm located in a single building or campus), or theymay be distributed at locations remote from one another (e.g., one ormore servers located in city A and one or more servers located in cityB). As used herein, each MTS could include one or more logically and/orphysically connected servers distributed locally or across one or moregeographic locations. Additionally, the term “server” is meant toinclude a computer system, including processing hardware and processspace(s), and an associated storage system and database application(e.g., OODBMS or RDBMS) as is well known in the art. It should also beunderstood that “server system” and “server” are often usedinterchangeably herein. Similarly, the database object described hereincan be implemented as single databases, a distributed database, acollection of distributed databases, a database with redundant online oroffline backups or other redundancies, etc., and might include adistributed database or storage network and associated processingintelligence.

FIG. 7 also illustrates environment 610. However, in FIG. 7 elements ofsystem 616 and various interconnections in an embodiment are furtherillustrated. FIG. 7 shows that user system 612 may include processorsystem 612A, memory system 612B, input system 612C, and output system612D. FIG. 7 shows network 614 and system 616. FIG. 7 also shows thatsystem 616 may include tenant data storage 622, tenant data 623, systemdata storage 624, system data 625, User Interface (UI) 730, ApplicationProgram Interface (API) 732, PL/SOQL 734, save routines 736, applicationsetup mechanism 738, applications servers 700 ₁-700 _(N), system processspace 702, tenant process spaces 704, tenant management process space710, tenant storage area 712, user storage 714, and application metadata716. In other embodiments, environment 610 may not have the sameelements as those listed above and/or may have other elements insteadof, or in addition to, those listed above.

User system 612, network 614, system 616, tenant data storage 622, andsystem data storage 624 were discussed above in FIG. 6. Regarding usersystem 612, processor system 612A may be any combination of one or moreprocessors. Memory system 612B may be any combination of one or morememory devices, short term, and/or long term memory. Input system 612Cmay be any combination of input devices, such as one or more keyboards,mice, trackballs, scanners, cameras, and/or interfaces to networks.Output system 612D may be any combination of output devices, such as oneor more monitors, printers, and/or interfaces to networks. As shown byFIG. 7, system 616 may include a network interface 620 (of FIG. 6)implemented as a set of HTTP application servers 700, an applicationplatform 618, tenant data storage 622, and system data storage 624. Alsoshown is system process space 702, including individual tenant processspaces 704 and a tenant management process space 710. Each applicationserver 700 may be configured to tenant data storage 622 and the tenantdata 623 therein, and system data storage 624 and the system data 625therein to serve requests of user systems 612. The tenant data 623 mightbe divided into individual tenant storage areas 712, which can be eithera physical arrangement and/or a logical arrangement of data. Within eachtenant storage area 712, user storage 714 and application metadata 716might be similarly allocated for each user. For example, a copy of auser's most recently used (MRU) items might be stored to user storage714. Similarly, a copy of MRU items for an entire organization that is atenant might be stored to tenant storage area 712. A UI 730 provides auser interface and an API 732 provides an application programmerinterface to system 616 resident processes to users and/or developers atuser systems 612. The tenant data and the system data may be stored invarious databases, such as one or more Oracle™ databases.

Application platform 618 includes an application setup mechanism 738that supports application developers' creation and management ofapplications, which may be saved as metadata into tenant data storage622 by save routines 736 for execution by subscribers as one or moretenant process spaces 704 managed by tenant management process 710 forexample. Invocations to such applications may be coded using PL/SOQL 734that provides a programming language style interface extension to API732. A detailed description of some PL/SOQL language embodiments isdiscussed in commonly owned U.S. Pat. No. 7,730,478 entitled, “Methodand System for Allowing Access to Developed Applicants via aMulti-Tenant Database On-Demand Database Service”, issued Jun. 1, 2010to Craig Weissman, which is incorporated in its entirety herein for allpurposes. Invocations to applications may be detected by one or moresystem processes, which manage retrieving application metadata 716 forthe subscriber making the invocation and executing the metadata as anapplication in a virtual machine.

Each application server 700 may be communicably coupled to databasesystems, e.g., having access to system data 625 and tenant data 623, viaa different network connection. For example, one application server 700₁ might be coupled via the network 614 (e.g., the Internet), anotherapplication server 700 _(N-1) might be coupled via a direct networklink, and another application server 700 _(N) might be coupled by yet adifferent network connection. Transfer Control Protocol and InternetProtocol (TCP/IP) are typical protocols for communicating betweenapplication servers 700 and the database system. However, it will beapparent to one skilled in the art that other transport protocols may beused to optimize the system depending on the network interconnect used.

In certain embodiments, each application server 700 is configured tohandle requests for any user associated with any organization that is atenant. Because it is desirable to be able to add and remove applicationservers from the server pool at any time for any reason, there ispreferably no server affinity for a user and/or organization to aspecific application server 700. In one embodiment, therefore, aninterface system implementing a load balancing function (e.g., an F5Big-IP load balancer) is communicably coupled between the applicationservers 700 and the user systems 612 to distribute requests to theapplication servers 700. In one embodiment, the load balancer uses aleast connections algorithm to route user requests to the applicationservers 700. Other examples of load balancing algorithms, such as roundrobin and observed response time, also can be used. For example, incertain embodiments, three consecutive requests from the same user couldhit three different application servers 700, and three requests fromdifferent users could hit the same application server 700. In thismanner, system 616 is multi-tenant, wherein system 616 handles storageof, and access to, different objects, data and applications acrossdisparate users and organizations.

As an example of storage, one tenant might be a company that employs asales force where each salesperson uses system 616 to manage their salesprocess. Thus, a user might maintain contact data, leads data, customerfollow-up data, performance data, goals and progress data, etc., allapplicable to that user's personal sales process (e.g., in tenant datastorage 622). In an example of a MTS arrangement, since all of the dataand the applications to access, view, modify, report, transmit,calculate, etc., can be maintained and accessed by a user system havingnothing more than network access, the user can manage his or her salesefforts and cycles from any of many different user systems. For example,if a salesperson is visiting a customer and the customer has Internetaccess in their lobby, the salesperson can obtain critical updates as tothat customer while waiting for the customer to arrive in the lobby.

While each user's data might be separate from other users' dataregardless of the employers of each user, some data might beorganization-wide data shared or accessible by a plurality of users orall of the users for a given organization that is a tenant. Thus, theremight be some data structures managed by system 616 that are allocatedat the tenant level while other data structures might be managed at theuser level. Because an MTS might support multiple tenants includingpossible competitors, the MTS should have security protocols that keepdata, applications, and application use separate. Also, because manytenants may opt for access to an MTS rather than maintain their ownsystem, redundancy, up-time, and backup are additional functions thatmay be implemented in the MTS. In addition to user-specific data andtenant specific data, system 616 might also maintain system level datausable by multiple tenants or other data. Such system level data mightinclude industry reports, news, postings, and the like that are sharableamong tenants.

In certain embodiments, user systems 612 (which may be client systems)communicate with application servers 700 to request and updatesystem-level and tenant-level data from system 616 that may requiresending one or more queries to tenant data storage 622 and/or systemdata storage 624. System 616 (e.g., an application server 700 in system616) automatically generates one or more SQL statements (e.g., one ormore SQL queries) that are designed to access the desired information.System data storage 624 may generate query plans to access the requesteddata from the database.

Each database can generally be viewed as a collection of objects, suchas a set of logical tables, containing data fitted into predefinedcategories. A “table” is one representation of a data object, and may beused herein to simplify the conceptual description of objects and customobjects. It should be understood that “table” and “object” may be usedinterchangeably herein. Each table generally contains one or more datacategories logically arranged as columns or fields in a viewable schema.Each row or record of a table contains an instance of data for eachcategory defined by the fields. For example, a CRM database may includea table that describes a customer with fields for basic contactinformation such as name, address, phone number, fax number, etc.Another table might describe a purchase order, including fields forinformation such as customer, product, sale price, date, etc. In somemulti-tenant database systems, standard entity tables might be providedfor use by all tenants. For CRM database applications, such standardentities might include tables for Account, Contact, Lead, andOpportunity data, each containing pre-defined fields. It should beunderstood that the word “entity” may also be used interchangeablyherein with “object” and “table”.

In some multi-tenant database systems, tenants may be allowed to createand store custom objects, or they may be allowed to customize standardentities or objects, for example by creating custom fields for standardobjects, including custom index fields. U.S. patent application Ser. No.10/817,161, filed Apr. 2, 2004, entitled “Custom Entities and Fields ina Multi-Tenant Database System”, and which is hereby incorporated hereinby reference, teaches systems and methods for creating custom objects aswell as customizing standard objects in a multi-tenant database system.In certain embodiments, for example, all custom entity data rows arestored in a single multi-tenant physical table, which may containmultiple logical tables per organization. It is transparent to customersthat their multiple “tables” are in fact stored in one large table orthat their data may be stored in the same table as the data of othercustomers.

While one or more implementations have been described by way of exampleand in terms of the specific embodiments, it is to be understood thatone or more implementations are not limited to the disclosedembodiments. To the contrary, it is intended to cover variousmodifications and similar arrangements as would be apparent to thoseskilled in the art. Therefore, the scope of the appended claims shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar arrangements. It is to be understood that theabove description is intended to be illustrative, and not restrictive.

1. A method comprising: upgrading a first set of application servers ofa plurality of application servers at one or more computing devices;holding a first set of requests received at the first set of applicationservers from being processed while the first set of application serversis being upgraded; upgrading a second set of application servers of theplurality of application servers upon completion of the first set ofapplication servers; holding a second set of requests received at thesecond set of application servers from being processed while the secondset of application servers is being upgraded; and resuming processing ofthe first set of requests at the upgraded first set of applicationservers.
 2. The method of claim 1, further comprising resumingprocessing of the second set of requests at the upgraded second set ofapplication servers.
 3. The method of claim 1, further comprisingselecting and retiring the first set of application servers prior toupgrading the first set of application servers, wherein upgradingincludes updating a first version to a second version.
 4. The method ofclaim 1, further comprising selecting and retiring the second set ofapplication servers prior to upgrading the second set of applicationservers, wherein upgrading includes updating the first version to thesecond version.
 5. The method of claim 1, wherein the one or morecomputing devices comprise one or more of a server computer, a laptopcomputer, a smartphone, a personal digital assistant (PDA), a handheldcomputer, an e-reader, a tablet computer, a notebook, a desktop personalcomputer (PC), a cluster-based computer, a set-top box, and a GlobalPositioning System (GPS)-based navigation system.
 6. A systemcomprising: a computing device having a memory to store instructions,and a processing device to execute the instructions, wherein theinstructions cause the processing device to: upgrade a first set ofapplication servers of a plurality of application servers at one or morecomputing devices; hold a first set of requests received at the firstset of application servers from being processed while the first set ofapplication servers is being upgraded; upgrade a second set ofapplication servers of the plurality of application servers uponcompletion of the first set of application servers; hold a second set ofrequests received at the second set of application servers from beingprocessed while the second set of application servers is being upgraded;and resume processing of the first set of requests at the upgraded firstset of application servers.
 7. The system of claim 6, wherein theprocessing device is further to resume processing of the second set ofrequests at the upgraded second set of application servers.
 8. Thesystem of claim 6, wherein the processing device is further to selectand retire the first set of application servers prior to upgrading thefirst set of application servers, wherein upgrading includes updating afirst version to a second version.
 9. The system of claim 6, wherein theprocessing device is further to select and retire the second set ofapplication servers prior to upgrading the second set of applicationservers, wherein upgrading includes updating the first version to thesecond version.
 10. The system of claim 6, wherein the one or morecomputing devices comprise one or more of a server computer, a laptopcomputer, a smartphone, a personal digital assistant (PDA), a handheldcomputer, an e-reader, a tablet computer, a notebook, a desktop personalcomputer (PC), a cluster-based computer, a set-top box, and a GlobalPositioning System (GPS)-based navigation system.
 11. A machine-readablemedium having stored thereon instructions which, when executed by amachine, cause the machine to: upgrade a first set of applicationservers of a plurality of application servers at one or more computingdevices; hold a first set of requests received at the first set ofapplication servers from being processed while the first set ofapplication servers is being upgraded; upgrade a second set ofapplication servers of the plurality of application servers uponcompletion of the first set of application servers; hold a second set ofrequests received at the second set of application servers from beingprocessed while the second set of application servers is being upgraded;and resume processing of the first set of requests at the upgraded firstset of application servers.
 12. The machine-readable medium of claim 11,wherein the machine is further to resume processing of the second set ofrequests at the upgraded second set of application servers.
 13. Themachine-readable medium of claim 11, wherein the machine is further toselect and retire the first set of application servers prior toupgrading the first set of application servers, wherein upgradingincludes updating a first version to a second version.
 14. Themachine-readable medium of claim 11, wherein the machine is further toselect and retire the second set of application servers prior toupgrading the second set of application servers, wherein upgradingincludes updating the first version to the second version.
 15. Themachine-readable medium of claim 11, wherein the one or more computingdevices comprise one or more of a server computer, a laptop computer, asmartphone, a personal digital assistant (PDA), a handheld computer, ane-reader, a tablet computer, a notebook, a desktop personal computer(PC), a cluster-based computer, a set-top box, and a Global PositioningSystem (GPS)-based navigation system